Devices are known in which a bottle of volatile liquid has an upwardly projecting wick and a heater is located in the vicinity of the upper end of the wick to accelerate the evaporation of volatile liquid from the wick. The bottle, wick and heater are retained within a housing which carries an electric plug. To operate the heater the device is plugged into a wall socket. Devices of this type commonly claim to allow control of the rate of evaporation of the volatile liquids, for example, by varying the distance between the heater and the wick.
Known prior art devices suffer from the drawback of efficiency and convenience. Typically the user has to manually change the apparatus from “normal” to “boost” mode, and then to switch it back to “normal” mode when this effect is no longer necessary (e.g. when the room is empty, or at night). Given the typical location of sources of electrical supply on walls (at a low level near the floor) or placement of electrical devices, this makes the switching process inefficient and inconvenient.
Timed devices are available which are configured to release air treatment agent at predefined time periods but these device are not capable of dynamically adjusting their operation to take account of changes in the surrounding environment.
In order to overcome some of the drawbacks associated with a device having a timer function, devices consisting of a combination of a timed functional with a motion sensor functional have been made available and go some way to addressing this problem, however, increased motion surrounding the device does not necessarily linearly equate to a need for increased air treatment agent.
To improve the known devices yet further to make them truly adaptive to their surrounding environment it has been suggested that an odour sensor could be included with such devices such that when the device's ‘electronic nose’ detects malodour or the like air treatment agent could be emanated, however, such devices are fraught with sensitivity and reliability issues which renders them largely unsuitable for mass commercialisation.
There is a need, therefore, for a device which overcomes the defects of the prior art.